The present invention rates to a process for the control of a machine tool by means of a data processing unit of the type wherein an operator feeds data relative to an article to be machined into the data processing unit, which in turn automatically derives control commands for the operation of the machine tool from such data.
A process of this type is generally disclosed in European Patent Application No. 44,192. In this process, the operator cooperates interactively with a data processing unit that controls the machine tool. The operator enters symbolically coded data concerning the configuration of the article to be produced. This data is evaluated by the data processing unit and processed into control commands for the operation of the machine tool.
The operation of a numerically controlled machine tool is determined by a plurality of variables. For the machine tool to operate optimally, data concerning the workpiece, the tool, the machine itself, the cutting process to be used, and general boundary conditions, such as life, wear, etc. must be taken into consideration.
The state of the art requires that all of these variables be taken into account. As a result, the operator must process considerable knowledge of these conditions and must be able to program the data processing unit which is to control the machine tool. The operator must therefore have extensive knowledge of the interrelationships of the individual variables and in addition must be familiar with a programming language. The programming procedure is extremely complex. Known data processing units for the determination of optimum operating data for the operation of a machine tool are not machine specific. If sets of data are to be obtained for the control of a certain given machine tool, the data of the machine specifically involved must be taken into consideration and entered during programming of the data processing unit, which substantially increases the labor required.
Furthermore, the variables for optimum machine performance depend extensively on each other, i.e., for an optimum operation of a machine tool the individual values must be correlated with each other. The changing of one variable may result in changes in one or several other variables.
The determination of control data for the machine tool essentially involves the so-called machining data determination. This determination comprises the selection of the optimum cutting edge geometry (dimensions of the bit, radii, form, deflection shoulders, etc.) and the choice of the correct bit type (i.e., the material of the cutting edge). In addition, the optimum cutting velocities and limiting rpm, including the drive gear of the required machine tool, must be determined. Furthermore, the feed for the tool slide, the cutting depth, the number of cuts, the minimum admeasure (the material to be cut in finishing or preliminary processing operations), the necessary working spindle capacity and the cutting edge contact time must be calculated.
It is an object of the present invention to provide a novel process for the control of a machine tool by means of a data processing unit, in which an operator is able to carry out an optimum metal cutting process without knowledge of a programming language and without specific familiarity with the individual mutual dependencies of the variables.